New Mexico (NM) is the only state with the capacity to fully monitor cervical cancer screening and HPV prevention using a state-wide woman-based informatics system under mandated reporting. We are thus uniquely positioned to address gaps in understanding HPV vaccine effectiveness within a multi-cultural US population suffering many health disparities. Project 3 will accomplish 4 overarching objectives using realworid population-based evaluations in NM. 1) Among NM women < 30 years of age, we have characterized the HPV genotype distribution in a population-based sample of 30,000 normal and 15,000 abnormal cytology specimens collected in 2007-2008. We will estimate the 5-year incidence rate for outcomes of all abnormal histopathologic diagnoses (CIN1, CIN2, and CIN3) during a time period when few screening women (<5- 10%) will have been vaccinated. This aim will provide baseline incidence rates to which subsequent HPV genotype-specific incidence rates among future vaccinated cohorts can be compared. 2) To evaluate the impact of vaccination on the incidence of cervical abnormalities, we will use the NM State-wide Immunization Information System to identify a cohort of young women age 14-18 who received HPV vaccine in 2007-2008 (-25,000 women) and a cohort of the same age who did not receive vaccine (-50,000 women). Using data linkage, we will estimate and compare the 5-year incidence rates of abnormal histologic diagnoses in these two cohorts through 2014. Although many hypothetical changes to cervical screening among HPV vaccinated women have been proposed, reductions in CIN incidence rates must be observed before modifications can be justified. 3) As an eariy measure of population effectiveness, we will characterize HPV genotype-specific changes in cytologic diagnoses (normal, ASC-US, LSIL, and HSIL) and histologic abnormalities (CIN1,2,3) realized through HPV vaccination as it is being implemented. To accomplish this aim, we will compare HPV genotype distributions among these diagnostic categories in women <25 years of age during two time periods, 2007-2008 and 2012-2013. In the later period, a significant proportion of women screening will have been vaccinated. 4) We will characterize population-based screening practices (e.g. Pap and HPV test utilization and intervals between abnormal diagnosis and biopsy or treatment) for NM women across 2007-2014 and reveal any changes potentially related to HPV vaccine uptake. These data are critical to effective integration of HPV vaccination and screening strategies, to understanding current practices vs. guidelines and to measuring any impact of vaccination on screening compliance.